I need your help to build a spectrum analyzer (or itīs a VU Meter?). In simple terms, I like to build a "row" of LEDs that iluminate from left to right, depending on dB power is applied. Apart of the LEDs and board, Do i need a special IC?

An LM3915 IC drives 10 LEDs as a logarithmic VU meter. Add a bandpass filter to each LM3915 to make a spectrum analyser.The input should have a peak detector stage with a quick rise-time and a slow fall-time so you can see quick momentary sounds.

Posted on Mar 27 2007, 04:45 PM So are you gonna mount it in your "very old (and very special) audio system" with a blown stereo led?

I wouldn't do that. It would kinda spoil it. This is what I'd go for:

No, thereīs an error conception. Iīd never modify an original system. The purpose was either build the analyzer and put it over the speakers.And I wonīt modify anything in the special system until really know ehy ed doesnīlit. That would be a crime!